JPH0732581B2 - Stepping motor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stepping motor capable of converting rotational movement of a rotor into linear movement of an output shaft.

[Problems to be solved by conventional technology and invention]

In order to convert rotary motion into linear motion, a conversion mechanism configured by combining mechanical elements such as a crank mechanism, an eccentric ring, a gear, a rack and pinion, a cam, and a belt is often used. However, these mechanical conversion mechanisms have large friction and are inefficient, and most of them cannot obtain an arbitrary amount of linear movement.

On the other hand, in the conventional stepping motor in which the rotor rotates by a certain fixed angle each time an input pulse is applied, only a rotational motion can be obtained.

Further, the linear stepping motors provided in the related art directly obtain linear motions, and do not convert rotational motions into linear motions. Moreover, in this linear stepping motor, the mover that moves along the stator is formed by using the soft magnetic steel having the permanent magnet and the salient pole, so that the mover is large and heavy. Therefore, the size of the whole is large, the cost is high, and the inertia of the mover is large, so that the response is not good, the vibration is large, and the damping characteristic is not good.

[Means for solving problems]

According to the present invention, a spiral magnetized band is provided on the outer circumference of a rotor, and S poles and N poles are alternately magnetized along the spiral direction in the magnetized band, and the inner surface of a stator that houses the rotor is provided. A plurality of salient poles around which windings are wound, and a plurality of tooth-shaped magnetic pole ends are formed at equal intervals along the axial direction of the stator at the tips of these salient poles. The pitch of the magnetic pole ends along the axial direction is a positive multiple of the pitch along the rotor axial direction between the S pole and the N pole adjacent to each other along the spiral direction of the magnetized band, and the output shaft supporting the rotor. The output shaft is slidably pierced through a bearing that rotatably supports the above, and the above-mentioned conventional problems are solved by such technical means.

[Action]

This stepping motor is operated by sequentially switching the excitation of the phases consisting of the salient poles of the stator and the winding, and the rotor is magnetically attracted so that the poles of the rotor face the excited phases. It is rotated by a certain step angle. At the same time as this rotation, the rotor is attracted to the outer periphery of the rotor every time the rotor rotates by one step angle by the magnetic attraction action, and the rotor between the different poles adjacent to each other along the spiral direction of the magnetizing zone. It is moved by the same amount as the pitch along the axial direction. In this way, since the rotor is moved in the axial direction with its rotation, the output shaft which supports this rotor and slidably penetrates the bearing is linearly moved.

〔Example〕

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

In the figure, 1 is a rotor, and 2 is a stator accommodating the rotor 1.

As shown in FIG. 2, the stator 2 is supported by a pair of bearing brackets 3 which are provided by being fitted into the stator support, for example, both ends of the stator 2 in this embodiment. Bearings 4 are mounted inside the brackets 3, respectively.

The bearings 4 rotatably support the output shaft 5 located on the axis of the stator 2. Output shaft 5
Penetrates the bearing 4 slidably, and a load is connected to one of the protruding shaft ends 5a.

The stepping motor of this embodiment illustrated in FIG. 2 is used as a power source for seek operation of a magnetic storage device or the like. Due to this, the bearing 6 is inserted in the groove 5b provided at the end of the shaft.
A load, that is, a head support 8 provided with a magnetic head 7 at its tip is attached via the. A part of the head support 8 is slidably fitted to a guide 9 fixed to the bearing bracket 3 on the side of the shaft end 5a, and is prevented from rotating by the guide 9, so that the magnetic head 7 is made a medium (magnetic field). disk)
It is designed to reciprocate in the radial direction along 10 points.

The rotor 1 is supported by the output shaft 5. The rotor 1 has, for example, a cylindrical shape, and a spiral magnetizing zone 11 is provided on the outer periphery of the rotor 1, for example, for one turn.

In the magnetizing zone 11, S poles and N poles are alternately magnetized along the spiral direction. In this embodiment, S
Six poles and six N poles are provided, and in the following description and the drawings, each pole is indicated with a suffix of 1 to 6 for easy identification. Further, Δx in FIG. 1 is the S pole and the N pole which are adjacent to each other along the spiral direction of the magnetizing zone 11.
The distance between the poles along the axial direction of the rotor 1, that is, the pitch between different poles is shown.

The stator 2 has a substantially cylindrical shape, is formed longer than the rotor 1, and has a plurality of, for example, eight salient poles 12 to 12 on its inner surface.
19 are integrally provided so as to project along the radial direction centered on the axis of the stator 2. Winding 20 on these salient poles 12-19,
21 are wound alternately.

Since the present embodiment shows a two-phase bipolar drive type stepping motor, the winding 20 is formed by the salient poles 12,
It is wound over 14, 16, 18 and has salient poles.
The winding directions of 12, 16 and salient poles 14, 18 are opposite to each other. Similarly, the winding wire 21 is wound over the salient poles 13, 15, 17, and 19, and also the salient poles 13, 17 and the salient poles.
The winding directions for 15 and 19 are opposite to each other.

A large number of tooth-shaped magnetic pole ends 22 are integrally formed at the tips of the salient poles 12 to 19 at equal intervals along the axial direction of the stator 2. The distance between two magnetic pole ends 22 adjacent to each other along the axial direction of the stator 2, that is, the pitch of the magnetic pole ends is determined to be an integral multiple of the pitch Δx between the S pole and the N pole, and in the case of the present embodiment. Since the step angle is 15 ° depending on the number of poles of the rotor 1 and the number of salient poles, 3Δx is set.

The stepping motor configured as described above is operated by switching the excitation phase as shown in the following table.

In other words, when the winding 20 is energized in step 1, the salient poles 12, 14, 16, 18 are excited respectively, but the salient poles 12, 16 and the salient poles 12 and 16 are excited due to the difference in the winding direction of the winding 20. 14 and 18 are excited with different polarities. In this case, salient poles 12, 16
Is excited to the N pole, and the salient poles 14 and 18 are excited to the S pole, respectively. Therefore, S1 of the rotor 1 with respect to the magnetic pole end 22 of each excitation phase 12, 14, 16, 18 is magnetically attracted by the magnetic attraction action. N2, S4, and N5 are stable at the positions facing each other. This state is shown in FIG.

Next, when the current of the winding 20 is cut off and the current is passed through the winding 21 and the process proceeds to step 2, the salient poles 13, 15, 17, and 19 are excited respectively, but the winding direction of the winding 21 is different. Salient poles 13 and 17
The salient poles 15 and 19 are excited with different polarities. In this case, the salient poles 13 and 17 are S poles, and the salient poles 15 and 19 are
Are respectively excited to the N poles, so that the magnetic attraction acts on the rotor 1 with respect to the magnetic pole ends 22 of the excitation phases 13, 15, 16, and 19.
Torque works so that N1, S3, N4, S6 face each other,
The rotor 1 rotates clockwise by 15 ° and stabilizes at the position shown in FIG.

Furthermore, in step 3, while turning off the current of the winding 21,
This time, a current in the opposite direction to that in step 1 is applied to the winding 20 to switch the excitation phase, so that the rotor 1 is further rotated by 15 ° in the clockwise direction by the magnetic attraction action. In the following step 4, the current of the winding 20 is cut off, and a current in the direction opposite to that in the case of step 2 is applied to the winding 21 to switch the excitation phase. Therefore, the rotor 1 is rotated clockwise by the magnetic attraction action. It is further rotated 15 °.

In this way, by switching the excitation phase according to the input pulse, the rotor 1 can be rotated clockwise by a required step, and by switching the excitation phase in the reverse order of the above description, the rotor 1 can be rotated. 1 can be rotated counterclockwise.

Since the respective poles of the rotor 1 are alternately provided in the magnetizing zone 11 along the spiral direction, the poles are magnetically attracted to each other and face the magnetic pole end 22 of the salient pole and are stable. At the same time, it is moved in the axial direction by Δx for one step at the same time. Therefore, depending on the number of steps, the rotor 1
And the output shaft 5 can be stepped forward or backward along the axial direction.

Thus, for example, the magnetic head 7 shown in FIG. 2 can be caused to seek the medium 10.

According to the stepping motor capable of converting the rotational motion of the rotor 1 into the reciprocating linear motion of the output shaft 5 as described above, the friction portion becomes extremely small as compared with the conventional mechanical conversion mechanism, and therefore the conversion is performed with high efficiency. In addition, the movement stroke of the output shaft 5, which is almost impossible with the conventional mechanical conversion mechanism, can be arbitrarily obtained, and even a minute stroke can be easily obtained.

At the same time, the total weight of the rotor 1 and the output shaft 5 can be made smaller than that of the mover of the conventional linear stepping motor, so that the inertia of the rotor 1 can be made extremely small. Therefore, the responsiveness can be enhanced, and the vibration can be reduced to improve the damping characteristic. Moreover, the stepping motor in which the rotor is rotated is generally smaller than the linear stepping motor, and the characteristics of the stepping motor of the present invention are not impaired, and the stepping motor of the present invention is driven by the same driving method as the conventional rotation-only stepping motor. it can.

Further, according to the present invention, as in the second embodiment shown in FIG. 5, a spiral magnetizing zone 11 in which S poles and N poles are alternately magnetized is provided over the outer circumference of the rotor 1 for two turns or more. Two or more articles may be provided and implemented. Since the structure other than these points is the same as that of the first embodiment, the description thereof will be omitted.

According to the second embodiment, since the magnetic attraction action can be performed at more places, the torque and thrust of the rotor 1 can be increased.

The above improvements in torque, etc. are due to the spiral magnetization band.
It is needless to say that 11 can be realized only by providing two or more turns on the outer circumference of the rotor 1 and by providing two or more threads.

Further, as shown in FIG. 6, the present invention may be carried out by removing the non-magnetized zone part other than the spiral magnetized zone 11 in the rotor 1 and forming the rotor 1 in a spiral shape as a whole. . The structure other than these points is the same as the first
The description is omitted because it is the same as the embodiment.

According to the embodiment shown in FIG. 3, the weight of the rotor 1 can be made extremely small, so that the inertia can be minimized, the response can be further improved, and the vibration can be further reduced to further improve the damping characteristic.

Needless to say, the technical idea of the third embodiment can be applied to the second embodiment.

Although each of the above-described embodiments is configured as described above, the present invention can be applied to various applications including various actuators, and the rotor may be driven by the unipolar method instead of the bipolar method. Further, the number of salient poles and the poles of the rotor, the pitch and the like can be arbitrarily determined according to the design specifications.

In addition, in carrying out the present invention, as long as it does not violate the gist of the invention, specific structures, shapes, positions, and materials of rotors, spiral magnetized bands, stators, salient poles, magnetic pole ends, output shafts, bearings, etc. It is needless to say that the above and the like can be configured and carried out in various modes without being limited to the above embodiments.

〔The invention's effect〕

According to the present invention having the structure described in the claims, the rotary motion of the rotor, which is impossible with the conventional stepping motor having the rotor, can be converted into the linear motion of the output shaft, and Linear motion can be easily obtained even with a minute stroke, and it can be driven by the same drive system as a conventional stepping motor that causes the rotor to perform only rotary motion, and the conversion efficiency from rotary motion of the rotor to linear motion is improved. Compared with a conventional mechanical conversion mechanism, it has a higher cost, and has a smaller inertia and a higher responsiveness than a linear motion by a conventional linear stepping motor, and it has less vibration and good damping characteristics.

[Brief description of drawings]

FIGS. 1 to 4 show a first embodiment of the present invention, FIG. 1 is a perspective view of a main part with a part cross-sectioned, and FIG. 2 is a schematic longitudinal side view of the whole shown with a load, FIG. FIG. 4 is a schematic sectional view in different states. FIG. 5 is a schematic cross-sectional side view of essential parts showing a second embodiment of the present invention. FIG. 6 is a schematic vertical cross-sectional side view of essential parts showing a third embodiment of the present invention. 1 ... Rotor, 2 ... Stator, 4 ... Bearing, 5 ... Output shaft, 11 ... Spiral magnetization band, 12-19 ... Salient pole, 2
0, 21 ... Winding, 22 ... Magnetic pole end.

Claims (4)

[Claims] 1. A spiral magnetized band is provided on the outer circumference of a rotor, and the magnetized band is provided with S along the spiral direction.
The poles and the N poles are alternately magnetized, and a plurality of salient poles around which windings are wound are projected on the inner surface of the stator housing the rotor,
A large number of tooth-shaped magnetic pole ends are formed at the tips of the salient poles at equal intervals along the axial direction of the stator, and the pitch of the magnetic pole ends along the axial direction of the stator is set to the spiral of the magnetizing band. The output shaft is slidable on a bearing that is a positive multiple of the pitch between the S pole and N pole adjacent to each other in the direction of the rotor axis direction and that rotatably supports the output shaft supporting the rotor. A stepping motor characterized by being penetrated into the. 2. The spiral magnetizing band according to claim (1), wherein S and N poles are alternately magnetized along the spiral direction, and the spiral magnetizing band is provided for two or more turns. Stepping motor characterized by 3. The spiral magnetization band according to claim (1) or (2), wherein the S and N poles are alternately magnetized along the spiral direction.
A stepping motor characterized by being provided with more than one strip. 4. The rotor according to any one of claims (1) to (3), wherein a non-magnetized portion other than the spiral magnetized band is removed from the rotor. A stepping motor characterized by having a spiral shape as a whole.